Is paradoxical sphincter reaction provoked by needle electrode electromyography?

In 10 patients with emptying disturbances, the anal sphincter reaction was investigated clinically and by electromyography with needle and wire electrodes to elucidate whether pain during the investigation could provoke the paradoxical sphincter reaction. In eight of the patients, the paradoxical reaction was easily felt at digital examination. Two patients complained of pain during the needle electrode recording; none complained during the wire electrode investigation. Nevertheless, all 10 patients had paradoxical sphincter reaction independent of the electrode used at electromyography. With careful clinical investigation, most cases of paradoxical sphincter reaction can be diagnosed. When this is inconclusive, the diagnosis should be confirmed by electromyography, preferably by the wire technique.